PROJECT SUMMARY/ABSTRACT Occupational noise is a widespread risk factor strongly linked to critical health hazards such as hearing loss, psychiatric disorders, increased blood pressure, and harmful biochemical, immune system, and birth-weight effects. In the United States, every year more than 30 million workers are exposed to hazardous noise levels, including 76% of mine workers. One in four of these workers (or 7.5 million Americans) will develop permanent hearing loss. Noise-related hearing loss has been listed as one of the most prevalent occupational health concerns for more than 25 years [1]. Four out of five mine workers have a hearing impairment when they reach retirement age [2]. Existing noise dosimeters are expensive and cannot effectively alert users when a noise hazard occurs because they either lack a noise hazard indicator within the user?s visual field or they do not have an indicator. To address this problem, Physical Optics Corporation (POC) proposes, in Phase II, to advance the development of our new Light-Alerting Personal Noise Dosimeter (LAND) system, which was prototyped and proven feasible in Phase I. The LAND is an inexpensive, smartphone-based noise dosimeter with an alerting feature that fills the existing gap in prevention of noise-related hearing impairment/loss in the U.S. workforce. LAND alerts a worker of a noise hazard via vibration and light signals placed in the worker?s visual field, thus the alerts cannot be missed by workers at any time during their workday. LAND provides accurate measurement of noise parameters inside and/or in proximity of the ear and performance of hearing protection devices in real time. In addition, LAND, for the first time, provides users with information about the maximal time they can spend in hazardous area. Use of commercial smartphone will make LAND affordable for widespread acceptance. These advantages make the LAND commercially attractive. LAND is designed to meet Mine Safety and Health Administration (MSHA) electrical safety regulations for coal mine environments. The potential markets for the proposed LAND include the mining and construction industries, transportation and military sectors, as well as bars, restaurants, and concert halls. As a result, POC?s proposed research will significantly and positively impact the hearing conservation program. In Phase I, POC successfully demonstrated the feasibility of the LAND system with a scaled-down prototype culminating in third-party testing at Odin Metrology, Inc. (Thousand Oaks, CA). LAND is flexible and convenient in use. It accurately measures noise exposure, provide efficient hazard alerts, and have small size, weight, power, and cost. We also determined the market for the LAND. The goal of Phase II is to develop and demonstrate a full-scale prototype system that is completely safe for mine use. Successful development of this technology will result in an entirely new low-cost noise dosimeter system that will provide both noise measurement and real-time user alerting, thus it can be widely adopted to address this pervasive problem, preventing hearing loss and other environmental noise-related afflictions while reducing the cost of conducting noise surveys and hearing conservation programs.